New SOL Dawn Furnace Burner Short Cycling

[MissLizzie]

Grew up tent camping, love road trips and poking around and a light came on- Travel Trailer! So jumped in and have met sooo many wonderful people in such a short period of time! Was recommended here from an InTech site member to throw this out: At Huntington Beach for my 2nd trip with 2024 SOL Dawn. So far so good but… the furnace burner cycles on and off when well below set temp. Fan continues to run but burner shuts off as soon as air heats up and ignites again about 30 seconds later. Repeat. So relying on my heated mattress pad for this trip. Purchased trailer new in October. Any idea before I bring it in to the dealer? Thnx all!

 

[SMR]

Welcome to the forum!

 

[John From Detroit]

Welcome.. Furnace may be cycling due to a high temp cut off inside the furnace..

Not sure how to figure it out other than hook some kind of indicator to the high temp sensor and observe. Also I'll leave to Gary how to fix (That's one I've never dealt with)

 

[MissLizzie]

Welcome.. Furnace may be cycling due to a high temp cut off inside the furnace..

Not sure how to figure it out other than hook some kind of indicator to the high temp sensor and observe. Also I'll leave to Gary how to fix (That's one I've never dealt with)

Thank you John. I’ll take it in. Running less than a minute when ambient temp in the 50s. Looking on the bright side that it’s cutting off too soon…. Big world, be safe, have fun!

 

[John From Detroit]

There is one thing.. If the flame sensor is not sensing flame. .the "less than a minute" suggests this

Now on most RVs they use what is called a single wire ignition system This means there is but one wire between the control board and the burner itself. This wire carries roughly 1000 Volts AC to generate a spark to light the flame. Then it switches to "Sense" mode.

Well, what it is looking for is about 1/2 volt DC coming back from the thermocouple sensor.

Imagine what happens to that sensitive detector chip if the transfer from Spark to Sense is not proper 1000 VAC or about 14141 volts PEAK on a chip designed to sense 1/2 volt... NOT GOOD.

Other issues are bad connections on that wire that will pass the 1000 just fine but the 1/2 can't make it past the corrosion

In the case of my Furnace a new main board from Dinosaur boards fixed it.

First thing I noticed upon unboxing is the quality of the board (Far greater than Attwood factory board)
Next a lovely little gas discharge tube.. This type of device is often used to protect against over voltage spikes (What I described above) Right next to what I suspect is that sensor chip.

Seem the engineers at Dino think same as me.

 

[8Muddypaws]

Welcome aboard!

We had a similar situation and found that the hot air coming out of the vent was rising directly to the thermostat. Dumb design.

We use a small electric heater or two about 90% of the time. They are much quieter too.